The conventional method for packaging hard butter and other hard fats is to use a substantially square container into which a polyethylene bag or liner, having a wide mouth similar to a garbage bag, is placed. The bag or liner is filled with molten fat, up to a level near the top of the container, and when filling is stopped the remainder of the bag is folded down onto the top of the molten fat layer and the container is closed, cooling and solidification then taking place.
One problem with this is that orienting such a bag or liner vertically within a confining structure causes the bag or liner to develop folds or creases, particularly vertical folds, which tend to become imbedded in the fat during hardening. This also occurs due to parts of the bag being folded over onto the layer of molten fat during closing of the container. The fat tends to set up in the bag like cement, making it necessary for the end user, such as an employee of candy company, to actually chip away at the fat to remove imbedded liner. This is both time consuming and wasteful of fat, and the end user, such as a candy manufacturer, has to employ extreme care to prevent pieces of bag or liner from flowing into the end product being manufactured. Although filters are usually employed in the manufacture of most end products of the type contemplated, frequent cleaning of the filters is required, adding to manufacturing costs.
Another problem is that conventional polyethylene bags or liners fail to adequately protect the fats from moisture and air penetration during storage, shortening the shelf life of the fat. Depending upon product, a normal shelf life of fats may be as little as 2-3 months with conventional packaging.
Another method for packaging hard fats and butters is to use a simple plastic pail into which the molten fat is disposed. One problem with this is that the fats tend to leach polymers from the container, adversely affecting the flavor and shelf life of the fat product being stored. Also, removal of product from such a pail is difficult, generally requiring the application of heat, which adds to the costs involved.
Many other forms of packaging of molten and liquid materials have been proposed. For instance, U.S. Pat. No. 2,127,401 to Gillican, describes a packaging system for rosin. During packaging, the rosin is maintained in a molten condition at a temperature of 150.degree.-350.degree. F., and it is poured into a bag which is disposed in a supporting frame. Before the rosin cools and solidifies to any substantial extent, the bag is removed from the frame and placed on one of its broad sides. It is indicated in the patent that the bag, while in the frame, tends to develop wrinkles which crease and deform. If the rosin solidifies while the bag is in this configuration, the irregularities in the bag form lines of cleavage which make it easy for pieces of the rosin to break off during handling. Also, there is said to be a tendency in creases and fold areas for the rosin to soak into the bag, which on solidification makes it difficult for the bag to be removed. The bag is a conventional paper bag, which would not be suitable for use with molten fats. Also, the bag is, when placed in the supporting frame, provided with an open top used for filling, which, after filling, is sealed. The procedure in the Gillican patent also differs from the present invention in that the bag, once placed on a broad side, is not confined by any retaining structure.
Prior U.S. Pat. No. 2,383,352 to Snyder, describes a packaging system said to be suitable for packaging such products as lard, margarine and processed cheese, wherein the same may be placed into a bag in a hot, plastic condition and allowed to cool and set while contained in the bag. Cooling and solidifying can take place while the bag is retained in a box, the bag then being removed from the box by inverting the box. The bag is said to be an air-tight lining of rubber hydrochloride film (col. 4 of the patent). The box is not a shipping carton, nor does solidification take place while the bag is on a broad side.
Patents directed to bags having filler nozzles on a broad side thereof are U.S. Pat. Nos. 3,242,951 to Curie et al; 4,360,996 to Rutter; and 4,386,634 to Ellert. Other than use of a nozzle on a broad side of the bag, the disclosures of these patents do not relate to the concepts of the present invention. Also of interest in the prior art are U.S. Pat. Nos. 2,920,967 to Heinemann; 3,007,608 to Cox, Jr.; 3,299,603 to Shaw; and 3,314,210 to Jarund. These patents disclose primarily methods for packaging liquids.